The drag force, Fd, imposed by the surrounding air on a vehicle moving with velocity V is given by Fd = CdA^1/2V^2
where Cd is a constant called the drag coefficient, A is the projected frontal area of the vehicle, and r is the air density. Determine the power, in hp, required to overcome aerodynamic drag for an automobile moving at:

a. 25 miles per hour.
b. 70 miles per hour. Assume Cd = 0.28, A = 25 ft^2, and rho = 0.075 lb/ft^2.